Ophthalmologic microscope and function expansion unit

ABSTRACT

The object of the present invention is to develop an ophthalmologic microscope of a new method that increases the degree of freedom in the optical design in the Galilean ophthalmologic microscope provided with an OCT optical system. The present invention provides an ophthalmologic microscope, wherein an observation optical system, an objective lens, and an OCT optical system are placed in such a way that the optical axis of the OCT optical system does not penetrate through objective lens, and the optical axis of the observation optical system and the optical axis of the OCT optical system are non-coaxial, and wherein the ophthalmologic microscope further comprises a SLO optical system that scans a light ray which is a visible ray, a near infrared ray, or an infrared ray and guides the light to the subject&#39;s eye so as to become substantially coaxial with the optical axis of the OCT optical system.

RELATED APPLICATIONS

The present U.S. patent application is a divisional application of U.S.application Ser. No. 16/616,564 filed Nov. 25, 2019, which is a U.S.national-stage application under 35 U.S.C. § 371 of InternationalApplication No. PCT/JP2018/020084 filed on May 24, 2018. This presentapplication claims priority under 35 U.S.C. § 119 and the ParisConvention for the Protection of Industrial Property to Japanese PatentApplication No. 2017-103242, filed May 25, 2017; Japanese PatentApplication No. 2017-165187, filed Aug. 30, 2017; and Japanese PatentApplication 2018-057091, filed Mar. 23, 2018. The entire disclosures ofthe foregoing Japanese Patent Applications, U.S. patent application Ser.No. 16/616,564, and International Application No. PCT/JP2018/020084 areincorporated herein by reference.

TECHNICAL FIELD

The present invention relates to an ophthalmologic microscope comprisingan illuminating optical system for illuminating a subject's eye and anobservation optical system for observing the subject's eye, such as afundus camera, a slit lamp, a microscope for ophthalmic surgery. Theinventive ophthalmologic microscope is characterized in that itcomprises an OCT optical system capable of obtaining tomographic imagesof the subject's eye with Optical Coherence Tomography (abbreviated asOCT) and that the OCT optical system and an observation optical systemcan be independent from one another, and this can increase the degree offreedom in the design for ophthalmologic microscope.

The invention also relates to a function expansion unit detachable tothe ophthalmologic microscope and capable of adding functions of OCT tothe ophthalmologic microscope.

BACKGROUND ART

An ophthalmologic microscope is a medical or inspection equipment thatilluminates a subject's eye of a patient with an illuminating opticalsystem and enlarges it to observe with an observation optical systemconsisting of lens, etc. Such ophthalmologic microscopes that can obtaintomographic images of the subject's eye due to inclusion of an OCToptical system have been developed.

OCT is a technique that constitutes an interferometer using a lowcoherence (a short coherence length) light source, thereby obtainstomographic images of a biological body. In particular, it uses the lowcoherence light source, divides its light in half with a beam splitter,irradiates one of the lights (a measuring light) to the biologicaltissue to reflect or scatter, and reflects the other of the lights (areference light) with a mirror. The measuring light is reflected orscattered at a variety of depth of the biological tissue and numerousreflected or scattered light return. After converging the measuringlight returned to the beam splitter and the reflected light of thereference light, only the reflected or scattered light of the measuringlight which went through the same distance as the reference light isdetected interfering with the reflected light of the reference light.Therefore, intensities of the measuring light reflected at the variousdepth of the biological tissue can be detected by adjusting positions ofthe beam splitter and the mirror to variously change the path length ofthe reference light. With such OCT optical system, tomographic images ofa biological tissue can be obtained.

Providing this OCT optical system on an ophthalmologic microscopeenabled to obtain tomographic images of a retina and cornea of eye,iris, etc. and enabled to observe not only the surface but also internalcondition of tissues. This can improve diagnostic accuracy of eyediseases, and also improve the success rate in ophthalmic surgery.

For the ophthalmologic microscope comprising such OCT optical system,there is a need to incorporate the OCT optical system into themicroscope comprising the illuminating optical system and theobservation optical system such that the light of the OCT optical systemcan enter a subject's eye, and various methods have been developed.

For example, for a Galilean ophthalmologic microscope that comprises anobservation optical system consisting of observation optical systems forleft and right eyes of an observer, and comprises one objective lensthrough which the optical axes of the observation optical systems forleft and right eyes commonly penetrate, there is a method that makes thelight of OCT light source entered from the side of the objective lensreflect directly above the objective lens with a reflecting member andthen penetrate through the objective lens to enter the subject's eye(Patent documents 1 and 2, etc.).

Explaining more fully, as shown in FIG. 17 (a drawing citied from FIG. 1of Patent document 1), the ophthalmologic microscope comprises anobservation optical system consisting of lens groups 130, 140, 150, 170,180, that are pairs of left and right through which the optical axis ofthe observation optical system for left eye and the optical axis of theobservation optical system for right eye penetrate respectively, oneobjective lens 110 through which the optical axis of the observationoptical system for left eye and the optical axis of the observationoptical system for right eye commonly penetrate, OCT optical systems200, 250, 450, 460, 470, and illuminating optical systems 310, 320, 330.In the OCT optical system, the output light from the OCT light source200 is emitted through an optical fiber 250, converged with theilluminating light from the illuminating optical system at a beamcombiner 340 after being controlled its direction by two scanningmirrors 450, 460, and reflected at splitter 120 to enter a subject's eye1000.

Yet, for the Galilean ophthalmologic microscope, there is a method thatmakes the light of the OCT light source emit from the upper side of theobjective lens, penetrate through the objective lens, and enter asubject's eye (Patent document 3).

Moreover, for the Galilean ophthalmologic microscope, there is a methodthat makes the light path of the OCT optical system convergesubstantially coaxially with the light path of the observation opticalsystem, penetrate the objective lens, and enter a subject's eye (Patentdocuments 4 and 5).

All methods described above are ones that the optical axis of theobservation optical system and the optical axis of the OCT opticalsystem commonly penetrate through one objective lens.

For the Galilean ophthalmologic microscope, as a method that the opticalaxis of the OCT optical system does not penetrate through objectivelens, there is a method that makes the light of OCT light source enteredfrom the side of the objective lens reflect directly under the objectivelens with a reflecting member, and enter a subject's eye withoutpenetrating through the objective lens (Patent document 6).

Explaining more fully, as shown in FIG. 18 (a drawing cited from FIG. 2Aof Patent document 6), at the lower side of the objective lens 102through which the optical axis of the observation optical systempenetrates, the light of the OCT light source entered from the side ofthe objective lens is reflected at a dichroic mirror 400, and the lightof the OCT optical system enters a subject's eye.

In this method, the light path of the observation optical system and thelight path of the OCT optical system are converged coaxially directlyunder the objective lens.

Also, as a method different from the Galilean ophthalmologic microscope,there is a Greenough ophthalmologic microscope that comprises twoobjective lenses corresponding to the left and right observation opticalsystems, respectively, and sets the stereo angle between the left andright observation optical systems (Patent documents 7 and 8). In theGreenough ophthalmologic microscope, since there is no objective lensthrough which the optical axes of the left and right observation opticalsystems commonly penetrate, the light path of the OCT optical system canenter a subject's eye without penetrating through the objective lens.

However, the Greenough ophthalmologic microscope requires a complexoptical design in order to incline the left and right observationoptical systems each other to set the stereo angle.

While there is a Scanning Laser Ophthalmoscope (SLO) as a device forobserving a subject's eye, that irradiates a laser beam to the subject'seye and detects the reflected light, a device which combines SLO and OCThas also been developed (Patent document 9).

PRIOR ART REFERENCES Patent Documents

[Patent document 1] Japanese Unexamined Patent Application PublicationNo. H8-66421

[Patent document 2] Japanese Unexamined Patent Application PublicationNo. 2008-264488

[Patent document 3] Japanese Unexamined Patent Application PublicationNo. 2008-268852

[Patent document 4] Japanese Translation of PCT InternationalApplication Publication No. 2010-522055

[Patent document 5] Japanese Unexamined Patent Application PublicationNo. 2008-264490

[Patent document 6] U.S. Pat. No. 8,366,271 [Patent document 7] JapaneseUnexamined Patent Application Publication No. 2016-185177

[Patent document 8] Japanese Unexamined Patent Application PublicationNo. 2016-185178

[Patent document 9] Japanese Unexamined Patent Application PublicationNo. 2015-221091

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

As described above, for the conventional ophthalmologic microscopesprovided with the OCT optical system, there exist the Galileanophthalmologic microscope and the Greenough ophthalmologic microscope,however, the latter has required a complex optical design.

Also, for the conventional Galilean ophthalmologic microscope, althoughmany methods that the optical axis of the observation optical system andthe optical axis of the OCT optical system commonly penetrate throughone objective lens have been developed as indicated in Patent documents1 to 5, etc., the degree of freedom in the optical design is limitedbecause the OCT optical system and the observation optical system areinfluenced by each other as they are not independent from one another.

For the conventional Galilean ophthalmologic microscope, although themethod that the optical axis of the OCT optical system does notpenetrate through the objective lens has been developed as indicated inPatent document 6, there is a problem that the degree of freedom in theoptical design is limited, such as being not able to secure enoughdistance between the ophthalmologic microscope and a subject's eye,because of the optical members of the OCT optical system providedbetween the objective lens and the subject's eye.

Thus, in light of the conventional situation above, the object of thepresent invention is to develop, for the Galilean ophthalmologicmicroscope provided with OCT optical system, an ophthalmologicmicroscope of a new method that increases the degree of freedom in theoptical design.

Means for Solving the Problems

As a result of the keen research in order to solve the problems above,the inventors found that, for the Galilean ophthalmologic microscope,the observation optical system and the OCT optical system becomeindependent from one another by placing them in such a way the opticalaxis of the OCT optical system does not penetrate through the objectivelens through which the optical axis of the observation optical system,and the optical axis of the observation optical system and the opticalaxis of the OCT optical system are non-coaxial, which leads to increaseddegree of freedom in the optical design and also allows to detachablyunitize the OCT optical system. We came to complete the presentinvention with findings that, due to the optical axis of the observationoptical system and the optical axis of the OCT optical system beingnon-coaxial, a mismatch occurs between an image observed at theobservation optical system and an image obtained by the OCT opticalsystem, however, it is possible to observe a section of the subject'seye where the OCT optical system scans without a mismatch by providing aSLO optical system that guides a light ray substantially coaxial withthe optical axis of the OCT optical system to the subject's eye.

That is, the present invention provides the first invention belowregarding an ophthalmologic microscope, the second invention belowregarding a function expansion unit, and the third invention belowregarding a function expansion set.

(1) The first invention relates to an ophthalmologic microscopecomprising:

-   -   an illuminating optical system for illuminating a subject's eye;    -   an observation optical system that comprises an observation        optical system for left eye and an observation optical system        for right eye to observe the subject's eye illuminated by the        illuminating optical system;    -   an objective lens through which the optical axis of the        observation optical system for left eye and the optical axis of        the observation optical system for right eye of the observation        optical system commonly penetrate; and    -   an OCT optical system for scanning a measuring light to test the        subject's eye with Optical Coherence Tomography,        characterized in that the observation optical system, the        objective lens, and the OCT optical system are placed in such a        way that the optical axis of the OCT optical system does not        penetrate through the objective lens through which the optical        axis of the observation optical system penetrates, and the        optical axis of the observation optical system and the optical        axis of the OCT optical system are non-coaxial, and the        ophthalmologic microscope further comprises a SLO optical system        that scans a light ray which is a visible ray, a near infrared        ray, or an infrared ray and guides the light to the subject's        eye so as to become substantially coaxial with the optical axis        of the OCT optical system, and it can observe a section of the        subject's where the OCT optical system scans, with the SLO        optical system.

(2) In the first invention, it is preferable that the OCT optical systemcomprises:

-   -   a first optical member that guides a light from an OCT light        source to a first optical axis direction;    -   a first reflecting member that guides the light guided to the        first optical axis direction to a second optical axis direction        substantially perpendicular to the first optical axis direction;    -   a second optical member that relays the light guided to the        second optical axis direction;    -   a second reflecting member that guides the light relayed by the        second optical member to a third optical axis direction        substantially perpendicular to the second optical axis        direction; and    -   an objective lens for OCT that is placed on the third optical        axis direction and irradiates a prescribed section of the        subject's eye with the light guided to the third optical axis        direction.

(3) In any of ophthalmologic microscopes above, it is preferable tocomprise a deflection optical element that commonly scans a measuringlight of the OCT optical system and a light ray of the SLO opticalsystem.

(4) In any of ophthalmologic microscopes above, it is preferable thatthe objective lens has a partial shape of circular lens or a shape ofcircular lens with a cutout or hole, and that the optical axis of theOCT optical system penetrates through a portion where the objective lensdoes not exist, or through a cutout or hole provided in the objectivelens.

(5) In case of (4) above, it is possible to divide the circular lens orpart of the circular lens in two, with one of the divided lenses beingas the objective lens and the other being as an objective lens for OCTthrough which the optical axis of the OCT optical system penetrates.

(6) In any of ophthalmologic microscopes above, it is preferable tofurther comprise an objective lens position control mechanism thatadjusts a position of the objective lens or the objective lens for OCT.

(7) In any of ophthalmologic microscopes above, it is preferable thatthe OCT optical system and the SLO optical system are detachablyunitized.

(8) In any of ophthalmologic microscopes above, it is preferable tofurther comprise a detachable front-end lens onto a light path betweenthe subject's eye and the objective lens to observe a retina of thesubject's eye.

(9) The second invention relates to a function expansion unit used foran ophthalmologic microscope comprising: an illuminating optical systemfor illuminating a subject's eye, an observation optical system thatcomprises an observation optical system for left eye and an observationoptical system for right eye to observe the subject's eye illuminated bythe illuminating optical system, and an objective lens through which theoptical axis of the observation optical system for left eye and theoptical axis of the observation optical system for right eye of theobservation optical system commonly penetrate, characterized in that thefunction expansion unit comprises:

-   -   a joint detachable against the ophthalmologic microscope;    -   an OCT optical system for scanning a measuring light to test the        subject's eye with Optical Coherence Tomography; and    -   a SLO optical system that scans a light ray which is a visible        ray, a near infrared ray, or an infrared ray and guides the        light to the subject's eye;        wherein the optical axis of the OCT optical system does not        penetrate through the objective lens through which the optical        axis of the observation optical system penetrates, and the        optical axis of the observation optical system and the optical        axis of the OCT optical system are non-coaxial, when the        function expansion unit is attached to the ophthalmologic        microscope via the joint, and        wherein the optical axis of the OCT optical system and the        optical axis of the SLO optical system are substantially        coaxial, and the ophthalmologic microscope can observe a section        of the subject's where the OCT optical system scans, with the        SLO optical system.

(10) In the function expansion unit of the second invention, it ispreferable that the OCT optical system comprises:

-   -   a first optical member that guides a light from an OCT light        source to a first optical axis direction;    -   a first reflecting member that guides the light guided to the        first optical axis direction to a second optical axis direction        substantially perpendicular to the first optical axis direction;    -   a second optical member that relays the light guided to the        second optical axis direction;    -   a second reflecting member that guides the light relayed by the        second optical member to a third optical axis direction        substantially perpendicular to the second optical axis        direction; and    -   an objective lens for OCT that is placed on the third optical        axis direction and irradiates a prescribed section of the        subject's eye with the light guided to the third optical axis        direction.

(11) In any of function expansion units above, it is preferable tocomprise a deflection optical element that commonly scans a measuringlight of the OCT optical system and a light ray of the SLO opticalsystem.

(12) The third invention provides a function expansion set characterizedin that it comprises any of function expansion units above and anobjective lens for replacement to replace the objective lens.

(13) In the third invention, it is preferable that the objective lensfor replacement has a partial shape of circular lens or a shape ofcircular lens with a cutout or hole, and that when replacing theobjective lens with the objective lens for replacement and attaching thefunction expansion unit to the ophthalmologic microscope via the joint,the optical axis of the OCT optical system penetrates through a portionwhere the objective lens for replacement does not exist, or through acutout or hole provided in the objective lens for replacement.

Effect of the Invention

In the ophthalmologic microscope of the first invention, the opticalaxis of the OCT optical system does not penetrate the objective lensthrough, and the optical axis of the observation optical system and theoptical axis of the OCT optical system are non-coaxial. With thisconfiguration, the ophthalmologic microscope of the present invention isone which the observation optical system and the OCT optical system areindependent from one another. Therefore, in the ophthalmologicmicroscope of the present invention, as it is possible to performoptical design without the observation optical system and the OCToptical system being influenced each other, the ophthalmologicmicroscope of the present invention is effective in increasing thedegree of freedom in the optical design. Also, the ophthalmologicmicroscope of the present invention comprises a SLO optical system thatguides a light ray substantially coaxial with the optical axis of theOCT optical system to a subject's eye, thereby is effective in observingthe subject's eye without a mismatch from an image obtained by the OCToptical system.

For the function expansion unit of the second invention and the functionexpansion set of the third invention, the optical axis of the OCToptical system for the function expansion unit does not penetrate theobjective lens through which the optical axis of the observation opticalsystem for the ophthalmologic microscope penetrates, and the opticalaxis of the observation optical system for the ophthalmologic microscopeand the optical axis of the OCT optical system for the functionexpansion unit are non-coaxial. With this configuration, the OCT opticalsystem for the function expansion unit is independent from theobservation optical system for the ophthalmologic microscope, therebyallows for unitization and is effective in increasing the degree offreedom in the optical design. As the function expansion unit isdetachable to the ophthalmologic microscope via a joint, the functionexpansion unit and the function expansion set of the present inventionare effective in readily adding functions of OCT to the ophthalmologicmicroscope. Also, the function expansion unit and the function expansionset of the present invention comprise a SLO optical system that guides alight ray substantially coaxial with the optical axis of the OCT opticalsystem to a subject's eye, thereby are effective in observing thesubject's eye without a mismatch from an image obtained by the OCToptical system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates the configuration of an optical systemtaken from a side view, regarding to the ophthalmologic microscope ofthe first embodiment of the present invention.

FIG. 2 schematically illustrates the configuration of an optical systemtaken from a front view, regarding to the ophthalmologic microscope ofthe first embodiment of the present invention.

FIG. 3 schematically illustrates the optical configuration of an OCTunit used in the ophthalmologic microscope of the first embodiment ofthe present invention.

FIG. 4 schematically illustrates a displaying portion for displaying theobtained OCT images and SLO images on the ophthalmologic microscope ofthe first embodiment.

FIGS. 5A and 5B schematically illustrate shapes of an objective lensused for the ophthalmologic microscope of the first embodiment of thepresent invention. FIG. 5A is a view from the direction of the opticalaxis of the objective lens and FIG. 5B is a cross-sectional view alongthe plane including the line AA′ of FIG. 5A.

FIG. 6 schematically illustrates the configuration of an optical systemtaken from a side view, regarding to the ophthalmologic microscope ofthe second embodiment of the present invention.

FIG. 7 schematically illustrates the configuration of an optical systemtaken from a front view, regarding to the ophthalmologic microscope ofthe second embodiment of the present invention.

FIG. 8 is a perspective view of an OCT optical system, regarding to theophthalmologic microscope of the second embodiment of the presentinvention.

FIG. 9 is a plane view of an OCT optical system shown in FIG. 8 ,regarding to the ophthalmologic microscope of the second embodiment ofthe present invention.

FIG. 10 is a side view of an OCT optical system shown in FIG. 8 ,regarding to the ophthalmologic microscope of the second embodiment ofthe present invention.

FIG. 11 is a front view of an OCT optical system shown in FIG. 8 ,regarding to the ophthalmologic microscope of the second embodiment ofthe present invention.

FIGS. 12A and 12B schematically illustrate a shape of an objective lensused for the ophthalmologic microscope of the third embodiment of thepresent invention. FIG. 12A illustrates an objective lens seen from theoptical axis direction and FIG. 12B is a cross-sectional view of FIG.12A in the plane including a line AA′.

FIGS. 13A and 13B schematically illustrate a shape of an objective lensused for the ophthalmologic microscope of the fourth embodiment of thepresent invention. FIG. 13A is a view from the direction of the opticalaxis of the objective lens and FIG. 13B is a cross-sectional view ofFIG. 13 (A) in the plane including a line AK.

FIGS. 14A and 14B schematically illustrate a shape of objective lensused for the ophthalmologic microscope of the fifth embodiment of thepresent invention. FIG. 14A is a view from the direction of the opticalaxis of the objective lens and FIG. 14B is a cross-sectional view FIG.14A in the plane including a line AK.

FIGS. 15A and 15B schematically illustrate a shape of an objective lensused for the ophthalmologic microscope of the sixth embodiment of thepresent invention. FIG. 15A is a view from the direction of the opticalaxis of the objective lens and FIG. 15B is a cross-sectional view ofFIG. 15A in the plane including a line AK.

FIGS. 16A and 16B schematically illustrate a shape of an objective lensused for the ophthalmologic microscope of the seventh embodiment of thepresent invention. FIG. 16A is a view from the direction of the opticalaxis of the objective lens and FIG. 16B is a cross-sectional view ofFIG. 16A in the plane including a line AK.

FIG. 17 is a drawing cited from FIG. 1 of Patent document 1.

FIG. 18 is a drawing cited from FIG. 2A of Patent document 6.

DESCRIPTION OF EMBODIMENTS

1. Ophthalmologic Microscope

1-1. Summary of the Ophthalmologic Microscope of the Present Invention

The ophthalmologic microscope of the present invention relates to anophthalmologic microscope comprising: an illuminating optical system forilluminating a subject's eye; an observation optical system thatcomprises an observation optical system for left eye and an observationoptical system for right eye to observe the subject's eye illuminated bythe illuminating optical system; an objective lens through which theoptical axis of the observation optical system for left eye and theoptical axis of the observation optical system for right eye of theobservation optical system commonly penetrate, and an OCT optical systemfor scanning a measuring light to test the subject's eye with OpticalCoherence Tomography.

For the ophthalmologic microscope of the present invention, theobservation optical system, the objective lens, and the OCT opticalsystem are placed in such a way that the optical axis of the OCT opticalsystem does not penetrate through the objective lens through which theoptical axis of the observation optical system penetrates, and theoptical axis of the observation optical system and the optical axis ofthe OCT optical system are non-coaxial. With this configuration, theophthalmologic microscope of the present invention is one which theobservation optical system and the OCT optical system are independentfrom one another.

Therefore, in the ophthalmologic microscope of the present invention, asit is possible to perform optical design without the observation opticalsystem and the OCT optical system being not influenced each other, theophthalmologic microscope of the present invention is effective inincreasing the degree of freedom in the optical design.

For example, but not limited to, providing an OCT optical system with anobjective lens for OCT in addition to an objective lens of theobservation optical system and controlling the position of therespective objective lenses independently allow for an optical designthat adjusts the focus of the observation optical system and the focusof the OCT optical system independently. It also allows for an opticaldesign that separates the OCT optical system from the observationoptical system to make the OCT optical system a detachable unit to theophthalmologic microscope. Furthermore, it allows for an optical designthat can obtain 3D tomographic images in more detail by adding not onlyone but also a plurality of OCT optical systems to the ophthalmologicmicroscope.

Thus, as the optical axis of the observation optical system and theoptical axis of the OCT optical system are non-coaxial, the center of animage observed by the observation optical system (the portion overlappedwith the optical axis of the observation optical system) and the centerof an image obtained by the OCT optical system (the portion overlappedwith the optical axis of the OCT optical system) does not match and thusa mismatch occurs between both images. Therefore, it becomes difficultto accurately align the image observed by the observation optical systemand the image obtained by the OCT optical system.

However, the ophthalmologic microscope of the present invention furthercomprises a SLO optical system that scans a light ray which is a visibleray, a near infrared ray, or an infrared ray and guides the light to thesubject's eye so as to become substantially coaxial with the opticalaxis of the OCT optical system. This SLO optical system allows toobserve the subject's eye without any mismatch from an image obtained byOCT optical system. For example, by imaging the shape of fundus surfacewith the SLO optical system and displaying it on a part of thedisplaying portion (display), meanwhile making that image correspond toa tomographic image obtained by the OCT optical system and superimposingor displaying the tomographic image on other part of the displayingportion, it is possible for an observer to know exactly to which sectionof the fundus surface the tomographic image corresponds.

In the present invention, “ophthalmologic microscope” refers to amedical or inspection equipment that can enlarge a subject's eye toobserve, and it encompasses one not only for human but also for animal.“Ophthalmologic microscope” includes, for example, but not limited to, afundus camera, a slit lamp, a microscope for ophthalmic surgery, etc.

In the present invention, “illuminating optical system” is configured toinclude an optical element for illuminating a subject's eye. Theilluminating optical system may further include a light source, but itmay guide natural light to a subject's eye.

Also, in the present invention, “observation optical system” isconfigured to include an optical element that can observe a subject'seye with return light which is reflected/scattered from the subject'seye illuminated by the illuminating optical system. In the presentinvention, the observation optical system comprises an observationoptical system for left eye and an observation optical system for righteye, so it is possible to observe stereoscopically with binocular visionwhen generating a parallax in the image obtained by the left and rightobservation optical systems.

Also, “observation optical system” of the present invention may directlyobserve a subject's eye through an eyepiece lens, etc., may observe itby accepting a light with an imaging element, etc., for imaging, or maybe provided with both functions.

In the present invention, “OCT optical system” is configured to includean optical element that the measuring light of OCT passes through. TheOCT optical system may further include an OCT light source.

In the present invention, as an optical element used in “illuminatingoptical system”, “observation optical system”, “OCT optical system”, forexample, but not limited to, a lens, a prism, a mirror, a light filter,a diaphragm, a diffraction grating, a polarizing element, etc. can beused.

In the present invention, “objective lens” is a lens in theophthalmologic microscope, which is provided at the side of a subject'seye. “Objective lens” of the present invention does not include afront-end lens (loupe) inserted between an objective lens and asubject's eye to use.

In the present invention, the optical axis of the observation opticalsystem and the optical axis of the OCT optical system “are non-coaxial”means that directions of the optical axis of the observation opticalsystem and the optical axis of the OCT optical system are not identicalin the region between the objective lens of the ophthalmologicmicroscope and the subject's eye.

Although “objective lens” in the present invention is an objective lensthrough which the optical axis of the observation optical system forleft eye and the optical axis of the observation optical system forright eye commonly penetrate, the optical axis of the OCT optical systemdoes not penetrate through the objective lens as mentioned above. Also,the optical axis of the illuminating optical system may or may notpenetrate through the objective lens. An additional objective lens forilluminating can be provided when the optical axis of the illuminatingoptical system does not penetrate through the objective lens.

“A light ray which is a visible ray, a near infrared ray, or an infraredray” used in the SLO optical system of the ophthalmologic microscope ofthe present invention may be any kind of light ray including wave lengthin the visible area, near infrared area, or infrared area, butpreferably a highly directional light ray. More preferably, a laser beammay be used.

Also, the SLO optical system “becomes substantially coaxial” with theoptical axis of the OCT optical system means that the directions of theeach optical axis may be approximately identical in the main regionbetween the objective lens of the ophthalmologic microscope and thesubject's eye and thus there may be a small mismatch. Here, although thedirection of light waves since the light path of the OCT optical systemand the light path of the SLO optical system are both being scanned, theoptical axes of the optical systems in the center of the light paths maybe approximately coaxial. Even if there is a small mismatch between thedirections of the optical axes, it may be less than 6°, more preferablyless than 4°, yet more preferably less than 1°.

Although the ophthalmologic microscope of the present inventioncomprises an OCT optical system and a SLO optical system, it ispreferable to have a part of the OCT optical system and the SLO opticalsystem as a shared optical system from a perspective of downsizing thedevice. In particular, it is preferred to share a deflection opticalelement that scans a measuring light of the OCT optical system and alight ray of the SLO optical system.

When sharing a part of the optical systems, it is preferred to make theoptical axis of the OCT optical system and the optical axis of the SLOoptical system substantially coaxial at the side of a subject's eye andto separate a measuring light of the OCT optical system and a light rayof the SLO optical system at the side of a detecting system. In thiscase, for the separation of the measuring light and the light ray, forexample, characteristics such as the wavelength and deflection of thelight can be used to separate with a dichroic mirror and an opticalfilter, etc.

Because the scan range of the OCT optical system and the scan range ofthe SLO optical system are identical when converging a measuring lightof the OCT optical system and a light ray of the SLO optical system, andthen scanning them with the same deflection optical element, thealignment of the both images becomes easier.

The deflection optical element that the OCT optical system and the SLOoptical system share may be any optical element that can change thedirection of light and scan the light. For example, but not limited to,an optical element comprising a reflection portion that its orientationchanges, like a galvano mirror, a polygon mirror, a rotation mirror, aMEMS (Micro Electro Mechanical Systems) mirror, etc., and an opticalelement that can changes the direction of light with an electric fieldor acoustic-optic effects, like a deflection prism scanner and AOelement, can be employed.

1-2. First Embodiment

Hereinafter, examples of the embodiments of the present invention willbe fully described in reference to drawings.

FIGS. 1-4 schematically illustrate the first embodiment which is anexample of the ophthalmologic microscope of the present invention. FIG.1 is a schematic diagram from a side view of the configuration of anoptical system for the ophthalmologic microscope of the firstembodiment, and FIG. 2 is a schematic diagram from a front view. Also,FIG. 3 schematically illustrates the optical configuration of an OCTunit, FIG. 4 is a schematic diagram of a displaying portion fordisplaying obtained OCT images and SLO images, and FIG. 5 schematicallyillustrates a shape of objective lens.

As shown in FIG. 1 , the optical system of the ophthalmologic microscope1 comprises an objective lens 2, an illuminating optical system 300, anobservation optical system 400, an OCT optical system 500, and a SLOoptical system 1500.

The objective lens 2, the illuminating optical system 300, and theobservation optical system 400 are accommodated in an ophthalmologicmicroscope body 6. On the other hand, the OCT optical system 500 and theSLO optical system 1500 are accommodated in a function expansion unit 7.In FIG. 1 , the ophthalmologic microscope body 6 and the functionexpansion unit 7 are respectively indicated by dashed-dotted lines.

The ophthalmologic microscope body 6 and the function expansion unit 7are detachably coupled by a joint (not shown).

As shown in FIG. 1 , the illuminating optical system 300 illuminates asubject's eye 8 through the objective lens 2. The illuminating opticalsystem 300 is configured to include an illuminating light source 9, anoptical fiber 301, an emission opening diaphragm 302, a condenser lens303, an illuminating field diaphragm 304, a collimating lens 305, and areflecting mirror 306. The optical axis of the illuminating opticalsystem 300 is indicated by a dotted line O-300 in FIG. 1 .

The illuminating light source 9 is provided outside of theophthalmologic microscope body 6. The illuminating light source 9 isconnected to one end of the optical fiber 301. The other end of theoptical fiber is placed at the position facing the condenser lens 303the inside of the ophthalmologic microscope body 6. The illuminatinglight output from the illuminating light source 9 is guided by theoptical fiber 301 to enter the condenser lens 303.

The emission opening diaphragm 302 is provided at the position facingthe emission opening of the optical fiber 301 (a fiber end at thecondenser lens 303). The emission opening diaphragm 302 functions so asto block a partial region of the emission opening of the optical fiber301. Once the region blocked by the emission opening diaphragm 302 ischanged, the emission region of the illuminating light is changed.Thereby, the irradiation angle of the illuminating light, that is, anangle between the incident direction of the illuminating light againstthe subject's eye 8 and the optical axis of the objective lens 2 can bechanged.

The illuminating field diaphragm 304 is provided at the positionoptically conjugate to the front side focal position U0 of the objectivelens 2 (the position of X). The collimating lens 305 converts theilluminating light that passed through the illuminating field diaphragm304 into a parallel light flux. The reflecting mirror 306 reflects theilluminating light converted into a parallel light flux by thecollimating lens 305, towards the objective lens 2. The reflected lightis irradiated towards the subject's eye 8 through the objective lens 2.

(A part of) the illuminating light irradiated towards the subject's eye8 is reflected/scattered at the tissue of the subject's eye, such as acornea and retina. That reflected/scattered return light (also referredas “observed light”) penetrates through the objective lens 2 and entersthe observation optical system 400.

As shown in FIG. 1 , the observation optical system 400 is configured toinclude a variable magnification lens system 401, a beam splitter 402,an imaging lens 403, an image erecting prism 404, an eye width adjustingprism 405, a field diaphragm 406, and an eyepiece lens 407. The opticalaxis of the observation optical system 400 is indicated by a dotted lineO-400 in FIG. 1 .

The observation optical system 400 is used to observe the subject's eye8, which is being illuminated by the illuminating optical system 300,via the objective lens 2.

As shown in FIG. 1 , the OCT optical system 500 is configured to includean OCT unit 10, an optical fiber 501, a collimating lens 502, anilluminating field diaphragm 509, a dichroic mirror 1501, opticalscanners 503 a, 503 b, a relay optical system 504, a first lens group505, a reflecting mirror 508, a second lens group 506, and an objectivelens for OCT 507.

The optical axis of the OCT optical system 500 is indicated by a dottedline O-500 in FIG. 1 .

As shown in FIG. 1 , in the first embodiment, the optical axis of theOCT optical system O-500 does not penetrate through the objective lens2, the optical axis of the observation optical system O-400 and theoptical axis of the OCT optical system O-500 are non-coaxial, and thusthe OCT optical system and the observation optical system areindependent from one another.

The OCT unit 10 divides the light from a low coherence (short coherencelength) OCT light source into a measuring light and a reference light.The measuring light is guided by the OCT optical system 500 andirradiated towards the subject's eye 8, then it reflects/scatters at thetissue of the subject's eye and becomes a return light to be guided tothe OCT unit 10. The interference between the return light and thereference light of the measuring light is detected at the OCT unit 10.This allows to obtain tomographic images of the tissue of the subject'seye.

As shown in FIG. 1 , the OCT unit 10 is provided outside of the functionexpansion unit 7 but coupled with it by being connected to the one endof the optical fiber 501. The measuring light generated by the OCT unit10 emits from the other end of the optical fiber 501. The emittedmeasuring light is irradiated towards the subject's eye 8 by way of thecollimating lens 502, the illuminating field diaphragm 509, the dichroicmirror 1501, the optical scanners 503 a, 503 b, the relay optical system504, the first lens group 505, the reflecting mirror 508, the secondlens group 506, the objective lens for OCT 507, etc., and the returnlight of the measuring light reflected/scattered at the tissue of thesubject's eye 8 travels the same pathway in opposite direction andenters the other end of the optical fiber 501.

When observing a retina at the fundus of the eye, the front-end lens 14is inserted onto optical axes O-300, O-400, O-500 right in front of thesubject's eye by a moving means (not shown). In this case, the frontside focal position U0 of the objective lens 2 is conjugate to theretina 8 a at the fundus of eye.

Also, when observing an anterior eye part such as a cornea, an iris,etc., the observation is performed by eliminating the front-end lensfrom right in front of the subject's eye and aligning the front sidefocal position U0 with the anterior eye part.

As shown in FIG. 1 , the collimating lens 502 converts the measuringlight emitted from the other end of the optical fiber 501 into aparallel light flux. The collimating lens 502 and the other end of theoptical fiber 501 are configured to be relatively movable along theoptical axis of the measuring light. In the first embodiment, thecollimating lens 502 is configured to be movable, while the other end ofthe optical fiber 501 may be configured to be movable along the opticalaxis of the measuring light.

The illuminating field diaphragm 509 is conjugate to the front sidefocal position U0 of the objective lens 2. The dichroic mirror 1501 isconfigured with a reflecting member that transmits the measuring lightof the OCT optical system 500 without reflecting it.

The optical scanners 503 a, 503 b in the OCT optical system aredeflection optical elements that two-dimensionally deflect the measuringlight converted into a parallel light flux by the collimating lens 502.The optical scanner is a galvano mirror that includes a first scanner503 a comprising a deflection plane rotatable around a first axis and asecond scanner 503 b comprising a deflection plane rotatable around asecond axis orthogonal to the first axis. The relay optical system 504is provided between the first scanner 503 a and the second scanner 503b. The relay optical system 504 may not be provided, if the distancebetween the first scanner 503 a and the second scanner 503 b isshortened, etc.

The first lens group 505 is configured to include one or more lenses.The second lens group 506 also configured to include one or more lenses.The reflecting mirror 508 located between the first lens group 505 andthe second lens group 506 changes the direction of light towards thesubject's eye 8.

Moreover, the objective lens for OCT 507 is provided on the side havingcontact with the subject's eye 8.

The objective lens for OCT is configured to be movable along the opticalaxis, so it is possible to adjust the focus of the OCT optical system bycontrolling the position of the objective lens for OCT. This allows toadjust the focus of the OCT optical system to the position differentfrom the focus of the observation optical system.

Thus, in the ophthalmologic microscope of the first embodiment, sincethe optical axis of the OCT optical system O-500 does not penetratethrough the objective lens 2, and the optical axis of the observationoptical system O-400 and the optical axis of the OCT optical systemO-500 are non-coaxial, the observation optical system and the OCToptical system are independent from one another.

Therefore, in the ophthalmologic microscope of the first embodiment, itis possible to control the observation optical system and the OCToptical system independently, and it is also possible to have the OCToptical system as a unit detachable to the ophthalmologic microscope.

As shown in FIG. 1 , the ophthalmologic microscope 1 of the presentinvention further comprises a SLO optical system 1500. The SLO opticalsystem 1500 is configured to include a SLO light source 16, an opticalfiber 1502, a collimating lens 1503, an illuminating field diaphragm1504, a dichroic mirror 1501, a half mirror 1505, an optical diaphragm1506, a condensing lens 1507, a reflected light detector 1508, and animage generation part 1509.

The SLO light source 16 is provided outside of the function expansionunit 7 but coupled with it by being connected to the one end of theoptical fiber 1502. The light ray generated by the SLO light source 16emits from the other end of the optical fiber 1502. The emitted lightray is reflected at the half mirror 1505 through the collimating lens1503, the illuminating field diaphragm 1504, and also reflected at thedichroic mirror 1501 to converge coaxially to the measuring light of theOCT optical system 500.

As shown in FIG. 1 , the converged light ray of the SLO optical system1500 is two-dimensionally scanned at the optical scanners 503 a, 503 bsame as the measuring light of the OCT optical system 500. The functionexpansion unit 7 can be downsized/produced at a lower cost by commonlyusing the optical scanners 503 a, 503 b that require a complexmechanism, at the OCT optical system 500 and the SLO optical system1500.

In the ophthalmologic microscope of the present invention, it is alsopossible to scan the OCT optical system and the SLO optical systemindependently by providing separate optical scanners for the OCT opticalsystem and the SLO optical system respectively. This allows tosimultaneously scan different sites of an observed plane.

The light ray of the SLO optical system 1500 scanned at the opticalscanners 503 a, 503 b is irradiated towards the subject's eye 8 by wayof the relay optical system 504, the first lens group 505, thereflecting mirror 508, the second lens group 506, the objective lens forOCT 507, etc. Here, the optical axis of the SLO optical system O-500guided to the subject's eye 8 is coaxial with the optical axis of theOCT optical system O-500. And the return light of the light rayreflected/scattered at the tissue of the subject's eye 8 travels thesame pathway in opposite direction, and it is reflected at the dichroicmirror 1501, and detected at the reflected light detector 1508 afterpenetrating through the half mirror 1505 by way of the optical diaphragm1506, the condensing lens 1507. The detected signal is exchanged with animage by the image generation part 1509.

As shown in FIG. 1 , the dichroic mirror 1501 transmits the measuringlight of the OCT optical system 500 and reflects the light ray of theSLO optical system 1500. This allows to converge/separate the measuringlight of the OCT optical system 500 and the light ray of the SLO opticalsystem 1500.

The half mirror 1505 reflects some of the light ray of the SLO opticalsystem 1500 and transmits some. The half mirror 1505 allows to separatethe light source side and the light reception side of the SLO opticalsystem 1500.

The optical diaphragm 1506 is conjugate to the front side focal positionU0 of the objective lens 2, and the condensing lens 1507 concentratesthe light ray reflected/scattered at the subject's eye 8.

The reflected light detector 1508 comprises a light detection elementthat detects a weak light ray reflected/scattered at the subject's eye8, and it is configured with an APD (avalanche photodiode) or a photomultiplier tube, for example. The detected signal from the reflectedlight detector 1508 is sent to the image generation part 1509. Thescanned data of the subject's eye 8 is obtained by irradiating the lightray from the SLO light source 16 towards the subject's eye 8 whilescanning it with the optical scanners 503 a, 503 b, and detecting thelight ray reflected/scanned at the subject's eye 8 with the reflectedlight detector 1508. The image generation part 1509 generate an image ofthe subject's eye 8 based on this scanned data. This image is sent tothe display and displayed, and this allows to observe the form of thetissue of the subject's eye.

Based on the signal and image obtained by the SLO, it is possible totrack the movement of a subject's site during OCT scanning. Although amismatch occurs in a tomographic image obtained by the OCT if thesubject's eye moves during OCT scanning due to an involuntary eyemovement of the subject's eye, surgery operation, etc., it is possibleto obtain tomographic images of the OCT without a mismatch by detectingthe movement of the fundus based on the signal and image obtained by theSLO and scanning the OCT optical system in accordance with thismovement.

The ophthalmologic microscope of the first embodiment further will befurther fully described in reference to drawings.

FIG. 2 is a schematic diagram from a front view of the configuration ofan optical system for the ophthalmologic microscope of the firstembodiment.

As shown in FIG. 2 , the observation optical system is separated intoobservation optical systems for left eye 400L and for right eye 400R ofan observer, each comprising an observation light path. The optical axesof the left and right observation optical systems are indicated bydotted lines O-400L, O-400R, respectively, in FIG. 2 .

As shown in FIG. 2 , the left and right observation optical systems400L, 400R are each configured to include a variable magnification lenssystem 401, an imaging lens 403, an image erecting prism 404, an eyewidth adjusting prism 405, a field diaphragm 406, and an eyepiece lens407. Only the observation optical system for right eye 400R comprises abeam splitter 402.

The variable magnification lens system 401 is configured to include aplurality of zoom lenses 401 a, 401 b, 401 c. Each zoom lens 401 a, 401b, 401 c is movable along the optical axes of the left and rightobservation optical systems O-400L, O-400R with a variable powermechanism (not shown). This alters the magnification in observing orimaging the subject's eye 8.

As shown in FIG. 2 , the beam splitter 402 of the observation opticalsystem for right eye 400R separates some of the observed light guidedfrom the subject's eye 8 along the observation optical system for rightand guides it towards the imaging optical system. The imaging opticalsystem is configured to include an imaging lens 1101, a reflectingmirror 1102, and a television camera 1103.

The television camera 1103 is provided with an imaging element 1103 a.The imaging element 1103 a is configured with, for example, a CCD(Charge Coupled Devices) image sensor, a CMOS (Complementary Metal OxideSemiconductor) image sensor, etc. As an imaging element 1103 a, onecomprising a two-dimensional light reception plane (area sensor) isused.

The light reception plane of the imaging element 1103 a is placed at theposition optically conjugate to the front side focal position U0 of theobjective lens 2.

The beam splitter and the imaging optical system may exist in the bothright and left observation optical systems. It is possible to obtain astereoscopic image by retrieving images having parallax at respectiveright and left imaging elements.

Camera images can be used for obtaining an image of observation sitesand also for tracking OCT observation sites based on the obtainedsignals and images. It is possible to correct a mismatch due to aninvoluntary eye movement of the subject's eye during scanning with OCT,surgery operation, etc.

The image erecting prism 404 converts an inverted image to an erectingimage. The eye width adjusting prism 405 is an optical element foradjusting the distance between right and left light paths depending onthe eye width of an observer (distance between a left eye and a righteye). The field diaphragm 406 blocks a peripheral region in the crosssection of the observed light to restrict the observer's field of view.The field diaphragm 406 is provided at the position conjugate to thefront side focal position U0 of the objective lens 2 (the position ofX).

The observation optical systems 400L, 400R may be configured to includea stereo variator configured to be removal from the light path of theobservation optical system. The stereo variator is an optical axisposition altering element for altering the relative position of the axesof the left and right optical observation optical systems O-400L, O-400Rled respectively by the right and left variable magnification lenssystems 401. The stereo variator is, for example, evacuated to theevacuation position provided on the observer side for the observed lightpath.

In the ophthalmologic microscope of the first embodiment, asub-observation optical system 400S for an assistance observer to use isprovided in addition to the observation optical system for a mainobserver to use.

As shown in FIG. 2 , the sub-observation optical system 400S guides thereturn light (observed light) reflected/scattered at the subject's eye 8which is being illuminated with the illuminating optical system, towardsthe eyepiece lens for assistant 411 by way of the objective lens 2. Theoptical axis of the sub-observation optical system is indicated by adotted line O-400S in FIG. 2 .

The sub-observation optical system 400S is also provided with a pair ofright and left optical systems and capable of stereoscopic observationwith the binocular.

As shown in FIG. 2 , the sub-observation optical system 400S isconfigured to include a prism 408, a reflecting mirror 410, and aneyepiece lens for assistant 411. In the first embodiment, an imaginglens 409 is also placed between the prism 408 and the reflecting mirror410. The observed light from the subject's eye 8 penetrates through theobjective lens 2 and it is reflected by the reflecting surface 408 a ofthe prism 408. The observed light reflected by the reflecting surface408 a penetrates through the imaging lens 409 and it is reflected by thereflecting mirror 410 and guided to the eyepiece lens for assistant 411.

The observation optical systems 400L, 400R and the sub-observationoptical system 400S are accommodated in the ophthalmologic microscopebody 6.

When observing a retina at the fundus of the eye, the front-end lens 14is inserted onto optical axes O-400L, O-400R, O-400S right in front ofthe subject's eye by a moving means (not shown). In this case, the frontside focal position U0 of the objective lens 2 is conjugate to theretina 8 a at the fundus of eye.

Also, when observing an anterior eye part such as a cornea, an iris,etc., the observation is performed by eliminating the front-end lensfrom right in front of the subject's eye and aligning the front sidefocal position U0 with the anterior eye part.

FIG. 3 schematically illustrates the optical configuration of the OCTunit 10 used in the ophthalmologic microscope of the first embodiment.

In addition to the Fourier domain type illustrated below, the OCT may beother type of OCT, including a spectral domain type.

As shown in FIG. 3 , the OCT unit 10 constitutes an interferometer thatdivides the light emitted from the OCT light source unit 1001 into themeasuring light LS and the reference light LR and detects interferencebetween the measuring light LS and the reference light LR went throughdifferent light paths.

The OCT light source unit 1001 is configured to include a wavelengthscanning (wavelength sweeping) light source capable of scanning(sweeping) the wavelength of the emitted light, similar to the generalOCT device of the swept source type. The OCT light source unit 1001changes the output wavelength temporally for the near infraredwavelength which is unrecognizable by human eyes. The light output fromthe OCT light source unit 1001 is indicated by a symbol L0.

The light L0 output from the OCT light source unit 1001 is guided to thepolarized wave controller 1003 by the optical fiber 1002 and adjustedits polarizing condition. The polarized wave controller 1003 adjusts thepolarizing condition of the light L0 guided within the optical fiber1002 by applying stress to, for example, the loop-shaped optical fiber1002, from outside.

The light L0 whose polarizing condition has been adjusted by thepolarized wave controller 1003 is guided to the fiber coupler 1005 bythe optical fiber 1004 and divided into the measuring light LS and thereference light LR.

As shown in FIG. 3 , the reference light LR is guided by an opticalfiber 1006 to a collimator 1007 and converted into a parallel lightflux. The reference light LR which became a parallel light flux isguided to a corner cube 1010 by way of a light path length correctionmember 1008 and a dispersion compensation member 1009. The light pathlength correction member 1008 functions as a delay mean for matching thelight path lengths (optical distance) of the reference light LR and themeasuring light LS. The dispersion compensation member 1009 functions asa dispersion compensation mean for matching the dispersioncharacteristics (optical distance) of the reference light LR and themeasuring light LS.

The corner cube 1010 turns the reference light LR which was convertedinto a parallel light flux by the collimator 1007, from the advancingdirection to the opposite direction. The light path of the referencelight LR incident on the corner cube 1010 and the light path of thereference light LR emitted from the corner cube 1010 are parallel. Also,the corner cube 1010 will be movable to the direction along the incidentlight path and the emitting light path of the reference light LR. Thismovement alters the length of the light path of the reference light LR(reference light path).

As shown in FIG. 3 , the reference light LR through the corner cube 1010goes through the dispersion compensation member 1009 and the light pathlength correction member 1008, enters the optical fiber 1012 after it isconverted from a parallel light flux to a focused light flux by thecollimator 1011, and it is guided to the polarized wave controller 1013and adjusted its polarizing condition.

The polarized wave controller 1013 has a similar configuration to thepolarized wave controller 1003, for example. The reference light LRwhose polarizing condition has been adjusted by the polarized wavecontroller 1013 is guided to an attenuator 1015 by an optical fiber 1014and adjusted its light volume under control of an arithmetic controlunit 12. The reference light LR whose light volume has been adjusted bythe attenuator 1015 is guided to a fiber coupler 1017 by an opticalfiber 1016.

As seen from FIGS. 1 and 3 , the measuring light LS generated by thefiber coupler 1005 is guided to the collimating lens 502 by the opticalfiber 501. As shown in FIG. 1 , the measuring light incident on thecollimating lens 502 is irradiated towards the subject's eye 8 by way ofthe illuminating field diaphragm 509, the optical scanners 503 a, 503 b,the relay optical system 504, the first lens group 505, the reflectingmirror 508, the second lens group 506, and the objective lens for OCT507. The measuring light is reflected/scattered at various depthpositions of the subject's eye 8. The measuring light backscattered fromthe subject's eye 8 travels backwards the same pathway as the forwardroute and it is guided by the fiber coupler 1005 to reach the fibercoupler 1017 by way of the optical fiber 1018, as shown in FIG. 3 .

The fiber coupler 1017 synthesizes (causes the interference between) themeasuring light LS incident through the optical fiber 1018 and thereference light LR incident through the optical fiber 1016 to generatean interfering light. The fiber coupler 1017 generates a pair ofinterfering lights LC by branching the interfering light of themeasuring light LS and the reference light LR at a predeterminedbranching ratio (for example, 50:50). The pair of interfering lights LCemitted from the fiber coupler 1017 is guided to a detector 1021 by twooptical fibers 1019, 1020, respectively.

The detector 1021 is, for example, a Balanced Photo Diode (hereinafter,referred as “BPD”) that comprises a pair of photodetectors for detectinga pair of interfering lights LC respectively and thereby outputs adifference of detection results. The detector 1021 sends the detectionresult (detection signal) to the arithmetic control unit 12. Thearithmetic control unit 12 forms cross-sectional images by applying theFourier transformation, etc. to the spectral distribution based on thedetection result obtained by the detector 1021, for example, for each ofa series of wavelength scanning (per A line). The arithmetic controlunit 12 causes a displaying portion 13 to display the formed image.

Although the Michelson interferometer is employed in this embodiment, itis possible to appropriately employ any type of interferometer, forexample, Mach-Zehnder, etc.

FIG. 4 is a schematic diagram illustrating a displaying portion fordisplaying obtained OCT images and SLO images by the ophthalmologicmicroscope of the first embodiment.

As shown in FIG. 4 , the displaying portion 13 comprises a displayscreen 1301. The display screen 1301 is provided with six imagedisplaying portions 1302-1307. These image displaying portions are afirst longitudinal section image displaying portion 1302, across-sectional image displaying portion 1303, a processed imagedisplaying portion 1304, a front image displaying portion 1305, a secondlongitudinal section image displaying portion 1306, and a surgical guideimage displaying portion 1307, respectively.

The front image displaying portion 1305 displays an image of fundussurface obtained by the SLO optical system, and the first longitudinalsection image displaying portion 1302, the cross-sectional imagedisplaying portion 1303, and the second longitudinal section imagedisplaying portion 1306 display tomographic images of fundus obtained bythe OCT optical system. The processed image displaying portion 1304displays an image obtained by applying a predetermined processingtreatment to images displayed on other image displaying portions(processed images), for example, angiography, projection (fundustomographic image), an image for the detection of a lesion part such asa diabetic retinopathy. In FIG. 4 , the processed image displayingportion 1304 displays the image of fundus surface obtained by the SLOoptical system, with the section of lesion part being colored. Here, thesection of lesion part is specified by image-analyzing the tomographicimage obtained by the OCT.

As shown in FIG. 4 , the front image displaying portion 1305 displays anobservation image for fundus surface, with the lateral direction beingx-axis and the longitudinal direction being y-axis. And thecross-sectional image displaying portion 1303 displays a tomographicimage of fundus along the x-y cross section.

And the first longitudinal section image displaying portion 1302 and thesecond longitudinal section image displaying portion 1306 displaytomographic images of fundus along two cross sections of z direction,which are indicated by a dotted line in the front image displayingportion 1305. The first longitudinal section image displaying portion1302 displays a tomographic image of the y-z cross section and thesecond longitudinal section image displaying portion 1306 displays atomographic image of the x-z cross section.

The surgical guide image displaying portion 1307 can display, forexample, an image which is synthesized by superimposing a site in needof surgery on an image obtained before the surgery.

Here, in the ophthalmologic microscope of the first embodiment, there isno position mismatch between the observation image of fundus surfaceobtained by the SLO optical system and the tomographic image of fundusobtained by the OCT optical system, since the optical axis of the OCToptical system and the optical axis of the SLO optical system arecoaxial. This allows for the accurate position alignment as there is noposition mismatch between the observation image of fundus surfacedisplayed on the front image displaying portion 1305 and the tomographicimage of the x-y cross section displayed on the cross-sectional imagedisplaying portion 1303. Also, it allows for the accurate positionalignment as there is no position mismatch between two cross sectionsindicated by dotted lines at the front image displaying portion 1305,and the tomographic image of the y-z cross section displayed on thefirst longitudinal section image displaying portion 1302 and thetomographic image of the x-z cross section displayed on the secondlongitudinal section image displaying portion 1306.

FIG. 5 is a schematic diagram illustrating a shape of objective lensused for the ophthalmologic microscope of the first embodiment. FIG. 5(A) is a view from the direction of the optical axis of the objectivelens and FIG. 5 (B) is a cross-sectional view along the plane includingthe line AA′ of FIG. 5 (A).

As shown in FIG. 5 (A), the objective lens 2 used in the firstembodiment has a shape of circular lens with a hole 201 in its center.And the light path of the OCT optical system P-500 passes through thathole. And in the ophthalmologic microscope of the first embodiment, thelight path of the observation optical system for left eye P-400L, thelight path of the observation optical system for right eye P-400R, andthe light path of the illuminating optical system P-300 respectivelypenetrates through different sections of the objective lens 2. Also,although not shown, the light path of the sub-observation optical systempenetrates through in the proximity of the light path of the observationoptical system for left eye P-400L.

Next, as shown in FIG. 5 (B), the sectional shape of the objective lens2 has a shape of a convex lens with a hole in its center.

1-3. Shape of Objective Lens

Although a circular lens can be used as an objective lens for theophthalmologic microscope of the present invention, it is preferable todecrease the angle formed by the optical axis of the OCT optical systemand the optical axis of the observation optical system, and for thispurpose the objective lens having a partial shape of circular lens orthe objective lens having a shape of circular lens with a cutout or holeis preferably used.

In the present invention, “partial shape of circular lens” refers to ashape of circular lens which has been partially cut away in a plane viewfrom the optical axis direction of the lens, and for example, but notlimited to, the lens having a shape cut into a semicircular shape, a fanshape, a rectangular shape, etc. so that the light path of theobservation optical system for left eye and the light path of theobservation optical system for right eye penetrate through can be used.

Also, in the present invention, “shape of circular lens with a cutout orhole” refers to a shape with a cutout or hole in a plane view from theoptical axis direction of the lens, and for example, but not limited to,the lens having a shape provided with a cutout or hole in a portionthrough which the light path of the OCT optical system penetrates can beused.

To ensure enough space to place optical elements of the OCT opticalsystem, etc., the objective lens having a partial shape of circular lensis preferably used, rather than providing the circular lens with acutout or hole.

Using a lens with such shape, the light path of the OCT optical systemcan pass through the cutaway portion where there is no lens exist in acircular lens, or through the cutout or hole provided in the lens. Thisallows to decrease the angle formed by the optical axis of the OCToptical system and the optical axis of the observation optical systemwithout the optical axis of the OCT optical system penetrating throughthe objective lens.

In the present invention, the angle formed by the optical axis of theOCT optical system and the optical axis of the observation opticalsystem (either of optical axes of the right and left observation lightpaths) may be preferably between 1 and 15°, more preferably between 4and 10°, and yet preferably between 6 and 8°.

In the ophthalmologic microscope of the present invention, a circularlens or a lens consisting of part of a circular lens can be divided intotwo, and one of the divided lenses can be an objective lens throughwhich the optical axis of the observation optical system penetrates andthe other one of the divided lenses can be objective lens through whichthe optical axis of the OCT optical system penetrates.

Here, “lens consisting of part of a circular lens” can use lens having a“partial shape of circular lens” described above.

By using the divided lenses like this and making each of their positionsindependently controllable, it is possible to control the observationoptical system and the OCT optical system independently.

1-4. Second Embodiment

Preferably, the OCT optical system can be additionally incorporated asan extension function into the ophthalmologic microscope comprising anobservation optical system and an illuminating optical system. Toadditionally incorporate in this way, the inventors found that it can becompactly incorporated by bending the light path of the OCT opticalsystem twice to adapt to the original function of the microscope.

That is, in the ophthalmologic microscope of the present invention, theOCT optical system preferably comprises:

-   -   a first optical member that guides a light from an OCT light        source to a first optical axis direction;    -   a first reflecting member that guides the light guided to the        first optical axis direction to a second optical axis direction        substantially perpendicular to the first optical axis direction;    -   a second optical member that relays the light guided to the        second optical axis direction;    -   a second reflecting member that guides the light relayed by the        second optical member to a third optical axis direction        substantially perpendicular to the second optical axis        direction; and    -   an objective lens for OCT that is placed on the third optical        axis direction and irradiates a prescribed section of the        subject's eye with the light guided to the third optical axis        direction.

With this optical configuration, the OCT optical system can be compactlyincorporated by adapting to the original function of the ophthalmologicmicroscope.

Hereinafter, examples of the embodiments of the ophthalmologicmicroscope of the present invention comprising the OCT optical systemwhose light path has been bended twice will be fully described inreference to drawings.

FIGS. 6 and 7 schematically illustrate the second embodiment which is anexample of the ophthalmologic microscope of the present invention.

FIG. 6 is a side schematic view of an ophthalmologic microscope 1, andFIG. 7 is a front schematic view of the same.

As shown in FIGS. 6 and 7 , an OCT device 5 is arranged along with theophthalmologic microscope 1.

The ophthalmologic microscope 1 is provided with an illuminating opticalsystem 300 (not shown in FIG. 7 ), an observation optical system 400,and an OCT optical system 500.

The observation optical system 400 can observe a prescribed section ofthe subject's eye 8. As referenced in FIG. 6 , the illuminating opticalsystem 300 can illuminate a part of the subject's eye 8 to be observed.

The OCT device 5 arranged along with the ophthalmologic microscope 1 canobtain tomographic images of the subject's eye 8. The OCT optical system500 is incorporated into the ophthalmologic microscope 1 as a part ofthe OCT device 5. The round-trip guide light path of the measuring lightis constructed by the OCT optical system 500, the front-end lens 14, andthe reflecting surface of the subject's eye 8 (cornea, retina, etc.).

As specified in FIG. 7 , the observation optical system 400 comprises anobservation optical system for right eye 400R and an observation opticalsystem for left eye 400L. In FIG. 6 , the entire configuration is shownfor the observation optical system for right eye 400R, while only theobjective lens 2 to be shared with the observation optical system forright eye 400R is shown for the observation optical system for left eye400L.

Also, as specified in FIG. 7 , the optical axis O-400R of theobservation optical system for right eye 400R and the optical axisO-400L of the observation optical system for left eye 400L respectivelypass through the objective lens 2.

In this embodiment, as shown in FIG. 6 , the illuminating optical system300 and the observation optical system 400 are accommodated in anophthalmologic microscope body 6. Also, the OCT optical system 500 andthe SLO optical system 1500 are accommodated in a function expansionunit 7. In FIGS. 6 and 7 , the ophthalmologic microscope body 6 isindicated by a dashed-dotted line and the function expansion unit 7 isindicated by a dashed line.

The function expansion unit 7 is removably coupled to the ophthalmologicmicroscope body 6 via a joint (not shown).

As shown in FIGS. 6 and 7 , the OCT device 5 consists of an OCT unit 10and a function expansion unit 7.

The function expansion unit 7 accommodates an OCT optical system 500 andthe SLO optical system 1500 (not shown in FIG. 7 ).

FIG. 8 is a perspective view of the OCT optical system 500, FIG. 9 is aplane view of the same, FIG. 10 is a side view of the same, and FIG. 11is a front view of the same. However, in FIGS. 9 and 11 , a collimatinglens 502, a scanning function part 503, and a first optical member 510(described below) are not shown.

In FIGS. 8 and 10 , the OCT optical system 500 is configured to includea collimating lens 502, a scanning function part 503, a first opticalmember 510, a first reflecting member 511, a second optical member 512,a second reflecting member 513, and an objective lens for OCT 507.

The scanning function part 503 is a two-dimensional scanning mechanismthat comprises optical scanners 503 a, 503 b. The scanning function part503 is provided at the back side of the ophthalmologic microscope body 6(the far side from an observer). The first optical member 510 is an OCTimaging lens that guides a light scanned by the scanning function part503 to a direction of the first optical axis O-501. The first opticalaxis O-501 is formed from the far side to the near side at the positionnear the right outer side of the ophthalmologic microscope body 6 whenviewing it from the front, and the light scanned by the scanningfunction part 503 is guided on the first optical axis O-501 from the farside to the near side.

As shown in FIGS. 8, 9, 10, and 11 , the light guided on the firstoptical axis O-501 is guided to the direction of a second optical axisO-502 perpendicular to the direction of the first optical axis O-501 bythe first reflecting member 511.

In this embodiment, as shown in FIG. 7 , the second optical axis O-502is formed so as to face inward from the right outer side of theophthalmologic microscope body 6.

The second optical member 512 is placed on the second optical axisO-502, and the light passed through the second optical member 512 isreflected downward (direction substantially perpendicular to the secondoptical axis O-502) by the second reflecting member 513. This reflectinglight path is indicated by the third optical axis direction O-503.

In this embodiment, the objective lens 2 has a partial shape of circularlens which has been cut away to have a cutting plane substantiallyparallel to the optical axis O-400, as shown in FIG. 6 .

In this embodiment, the objective lens for OCT 507 is accommodated inthe cutaway portion of this circular lens.

The light guided by the third optical axis direction O-503 is focused ata predetermined position on a side of the subject's eye 8 by theobjective lens for OCT 507.

In FIGS. 6 and 7 , the front side focal position U0 of the objectivelens 2 is located before the subject's eye 8 and the front-end lens 14is placed between the subject's eye 8 and the front side focal positionU0.

The front-end lens 14 is a lens used when observing a retina at thefundus of the eye, and it is inserted onto optical axes O-300, O-400L,O-400R, O-503 right in front of the subject's eye by a moving means (notshown). In this case, the front side focal position U0 of the objectivelens 2 is conjugate to the retina at the fundus of eye. Also, whenobserving an anterior eye part such as a cornea, an iris, etc., theobservation is performed by eliminating the front-end lens 14 from rightin front of the subject's eye 8.

As described above, the optical axis O-503 of the OCT optical system 500passes through the objective lens for OCT 507 and it is away from theoptical axis O-400 of the observation optical system 400.

Therefore, the OCT optical system 500 and the observation optical system400 are independent of each other.

As shown in FIG. 6 , the SLO optical system 1500 is configured toinclude a SLO light source 16, an optical fiber 1502, a collimating lens1503, an illuminating field diaphragm 1504, a dichroic mirror 1501, ahalf mirror 1505, an optical diaphragm 1506, a condensing lens 1507, areflected light detector 1508, and an image generation part 1509.

The SLO light source 16 is provided outside of the function expansionunit 7 but coupled with it by being connected to the one end of theoptical fiber 1502. The light ray generated by the SLO light source 16emits from the other end of the optical fiber 1502. The emitted lightray is reflected at the half mirror 1505 by way of the collimating lens1503, the illuminating field diaphragm 1504, and also reflected at thedichroic mirror 1501 to converge coaxially to the measuring light of theOCT optical system 500.

As shown in FIG. 1 , the converged light ray of the SLO optical system1500 is two-dimensionally scanned at the optical scanners 503 a, 503 bsame as the measuring light of the OCT optical system 500. The functionexpansion unit 7 can be downsized/produced at a lower cost by commonlyusing the optical scanners 503 a, 503 b that require a complexmechanism, at the OCT optical system 500 and the SLO optical system1500.

Also in the ophthalmologic microscope of the second embodiment, there isno position mismatch between the observation image of fundus surfaceobtained by the SLO optical system and the tomographic image of fundusobtained by the OCT optical system, since the optical axis of the OCToptical system and the optical axis of the SLO optical system arecoaxial. As shown in FIG. 4 , this allows for the accurate positionalignment as there is no position mismatch between the observation imageof fundus surface displayed on the front image displaying portion 1305and the tomographic image of the x-y cross section displayed on thecross-sectional image displaying portion 1303. Also, it allows for theaccurate position alignment as there is no position mismatch between twocross sections indicated by dotted lines in the front image displayingportion 1305, and the tomographic image of the y-z cross sectiondisplayed on the first longitudinal section image displaying portion1302 and the tomographic image of the x-z cross section displayed on thesecond longitudinal section image displaying portion 1306.

1-5. Third Embodiment

A shape of an objective lens used in the third embodiment which is otherexample of the ophthalmologic microscope of the present invention isshown in FIG. 12 . FIG. 12 (A) illustrates an objective lens seen fromthe optical axis direction and FIG. 12 (B) is a cross-sectional view ofFIG. 12 (A) in the plane including a line AA′.

As shown in FIG. 12 (A), the objective lens 2 used in the thirdembodiment has a shape of circular lens with a partial cutout. And, thelight path of the OCT optical system P-500 passes through that cutoutportion.

And, as shown in FIG. 12 (B), the sectional shape of the objective lens2 has a partial shape of convex lens which has been partially cut away.

1-6. Fourth Embodiment

A shape of an objective lens used in the fourth embodiment which isother example of the ophthalmologic microscope of the present inventionis shown in FIG. 13 . FIG. 13 (A) illustrates an objective lens seenfrom the optical axis direction and FIG. 13 (B) is a cross-sectionalview of FIG. 13 (A) in the plane including a line AA′.

As shown in FIG. 13 (A), the objective lens 2 used in the fourthembodiment has a shape of circular lens which has been partially cutaway in a rectangular shape, and the light path of the observationoptical system for left eye P-400L and the light path of observationoptical system for right eye P-400R respectively penetrate throughdifferent sections of the objective lens 2. And the light path of theOCT optical system P-500 and the light path of the illuminating opticalsystem P-300 pass through in the proximity of the objective lens 2.

And, as shown in FIG. 13 (B), the sectional shape of the objective lens2 has a partial shape of convex lens which has been partially cut away.

1-7. Fifth Embodiment

A shape of an objective lens used in the fifth embodiment which is otherexample of the ophthalmologic microscope of the present invention isshown in FIG. 14 . FIG. 14 (A) illustrates an objective lens seen fromthe optical axis direction and FIG. 14 (B) is a cross-sectional viewFIG. 14(A) in the plane including a line AA′.

As shown in FIG. 14 (A), the objective lens 2 used in the fifthembodiment has a shape of circular lens which has been partially cutaway in a semicircular shape, and the light path of the observationoptical system for left eye P-400L, the light path of the observationoptical system for right eye P-400R, and the light path of theilluminating optical system P-300 respectively penetrate throughdifferent sections of the objective lens 2. And the light path of theOCT optical system P-500 passes through in the proximity of theobjective lens 2.

And, as shown in FIG. 14 (B), the sectional shape of the objective lens2 has a partial shape of convex lens which has been partially cut away.

1-8. Sixth Embodiment

A shape of an objective lens used in the sixth embodiment which is otherexample of the ophthalmologic microscope of the present invention isshown in FIG. 15 . FIG. 15 (A) illustrates an objective lens seen fromthe optical axis direction and FIG. 15 (B) is a cross-sectional view ofFIG. 15 (A) in the plane including a line AA′.

As shown in FIG. 15 (A), the objective lens 2 used in the sixthembodiment has a shape of circular lens which has been partially cutaway in a crescentic shape, and the light path of the observationoptical system for left eye P-400L, the light path of the observationoptical system for right eye P-400R, and the light path of theilluminating optical system P-300 respectively penetrate throughdifferent sections of the objective lens 2. And the light path of theOCT optical system P-500 passes through in the proximity of theobjective lens 2.

And, as shown in FIG. 15 (B), the sectional shape of the objective lens2 has a partial shape of convex lens which has been partially cut away.

1-9. Seventh Embodiment

Shapes of an objective lens and an objective lens for OCT used in theseventh embodiment which is other example of the ophthalmologicmicroscope of the present invention is shown in FIG. 16 . FIG. 16 (A)illustrates an objective lens seen from the optical axis direction andFIG. 16 (B) is a cross-sectional view of FIG. 16 (A) in the planeincluding a line AA′.

As shown in FIG. 16 (A), the objective lens and the objective lens forOCT used in the seventh embodiment is a circular lens divided in two.One of the divided lenses 2 is used as an objective lens, through whichthe light path of the observation optical system for left eye P-400L,the light path of the observation optical system for right eye P-400R,and the light path of the illuminating optical system P-300 penetrate.The other one of the divided lenses 507 is used as an objective lens forOCT, through which the light path of the OCT optical system P-500penetrates.

Also, as shown in FIG. 16 (B), the sectional shape of the objective lens2 and the objective lens for OCT 507 is a shape of convex lens dividedin two.

2. Function Expansion Unit

The function expansion unit of the present invention is detachable tothe ophthalmologic microscope and capable of adding functions of the OCTto the ophthalmologic microscope.

The function expansion unit of the present invention is used for anophthalmologic microscope comprising an illuminating optical system forilluminating a subject's eye, an observation optical system thatcomprises the light path of an observation optical system for left eyeand the light path of an observation optical system for right eye toobserve the subject's eye illuminated by the illuminating opticalsystem, and an objective lens through which the optical axis of theobservation optical system for left eye and the optical axis of theobservation optical system for right eye of the observation opticalsystem commonly penetrate.

And, the function expansion unit of the present invention comprises,

-   -   a joint detachable against the ophthalmologic microscope,    -   an OCT optical system for scanning a measuring light to test the        subject's eye with Optical Coherence Tomography, and    -   a SLO optical system that scans a light ray which is a visible        ray, a near infrared ray, or an infrared ray and guides the        light to the subject's eye, characterized in that the optical        axis of the OCT optical system does not penetrate through the        objective lens through which the optical axis of the observation        optical system penetrates, and the optical axis of the        observation optical system and the optical axis of the OCT        optical system are non-coaxial when the function expansion unit        is attached to the ophthalmologic microscope via the joint,        wherein the optical axis of the OCT optical system and the        optical axis of the SLO optical system are substantially        coaxial, and the ophthalmologic microscope can observe a section        of the subject's where the OCT optical system scans, with the        SLO optical system.

The OCT optical system for the function expansion unit of the presentinvention is independent from the observation optical system for theophthalmologic microscope, thereby allows for unitization and iseffective in increasing the degree of freedom in the optical design.Also, as the function expansion unit of the present invention isdetachable to the ophthalmologic microscope via a joint, it is effectivein readily adding functions of the OCT to the ophthalmologic microscope.Also, the function expansion unit of the present invention comprises aSLO optical system that guides a light ray substantially coaxial withthe optical axis of the OCT optical system to the subject's eye, therebyis effective in observing the subject's eye without a mismatch from animage obtained by the OCT optical system.

“Joint” in the function expansion unit of the present invention is notparticularly limited as long as it makes the function expansion unitdetachable to the ophthalmologic microscope, and can be, for example,but not limited to, a joint for coupling by a fitting or a joint forcoupling by using a screw.

A concrete example of the function expansion unit of the presentinvention is as described as the function expansion unit in theophthalmologic microscope of the first embodiment and the ophthalmologicmicroscope of the second embodiment (portion indicated by the symbol 7in FIGS. 1, 6, and 7 which is surrounded by the dashed-dotted lines).

3. Function Expansion Set

The function expansion set of the present invention is a set includingthe function expansion unit described in 2 above and the objective lensfor replacement for replacing objective lens of the ophthalmologicmicroscope.

Here, the objective lens having a shape described in 1-3 above can beused as an objective lens for replacement.

A concrete example of the objective lens for replacement can include theobjective lens used in the first embodiment and the third or seventhembodiment above (FIGS. 5 and 12-16 ).

As the function expansion set of the present invention is detachable tothe ophthalmologic microscope via a joint, it is effective in readilyadding functions of the OCT to the ophthalmologic microscope. Also, thefunction expansion set of the present invention comprises a SLO opticalsystem that guides a light ray substantially coaxial with the opticalaxis of the OCT optical system to the subject's eye, thereby iseffective in observing the subject's eye without a mismatch from animage obtained by the OCT optical system.

INDUSTRIAL APPLICABILITY

The ophthalmologic microscope, the function expansion unit, the functionexpansion set of the present invention are useful in the industry ofmanufacturing ophthalmic medical equipment.

EXPLANATION OF SYMBOLS

Symbols used in FIGS. 1-16 will be explained below:

-   -   1 ophthalmologic microscope    -   2 objective lens    -   300 illuminating optical system    -   301 optical fiber    -   302 emitted light diaphragm    -   303 condenser lens    -   304 illuminating field diaphragm    -   305 collimating lens    -   306 reflecting mirror    -   400 observation optical system    -   400L observation optical system for left eye    -   400R observation optical system for right eye    -   400S sub-observation optical system    -   401 variable magnification lens system    -   401 a, 401 b, 401 c zoom lens    -   402 beam splitter    -   403 imaging lens    -   404 image erecting prism    -   405 eye width adjusting prism    -   406 field diaphragm    -   407 eyepiece lens    -   408 prism    -   408 a reflecting surface of prism    -   409 imaging lens    -   410 reflecting mirror    -   411 eyepiece lens for assistant    -   5 OCT device    -   500 OCT optical system    -   501 optical fiber    -   502 collimating lens    -   503 scanning function part    -   503 a, 503 b optical scanner    -   504 relay optical system    -   505 first lens group    -   506 second lens group    -   507 objective lens for OCT    -   508 reflecting mirror    -   509 illuminating field diaphragm    -   510 first optical member    -   511 first reflecting member    -   512 second optical member    -   513 second reflecting member    -   6 ophthalmologic microscope body    -   7 function expansion unit    -   8 subject's eye    -   8 a retina    -   9 illuminating light source    -   10 OCT unit    -   1001 OCT light source unit    -   1002 optical fiber    -   1003 polarized wave controller    -   1004 optical fiber    -   1005 fiber coupler    -   1006 optical fiber    -   1007 collimator    -   1008 light path length correction member    -   1009 dispersion compensation member    -   1010 corner cube    -   1011 collimator    -   1012 optical fiber    -   1013 polarized wave controller    -   1014 optical fiber    -   1015 attenuator    -   1016 optical fiber    -   1017 fiber coupler    -   1018 optical fiber    -   1019 optical fiber    -   1020 optical fiber    -   1021 detector    -   1101 imaging lens    -   1102 reflecting mirror    -   1103 television camera    -   1103 a imaging element    -   12 arithmetic control unit    -   13 displaying portion    -   1301 display screen    -   1302 first longitudinal section image displaying portion    -   1303 cross-sectional image displaying portion    -   1304 processed image displaying portion    -   1305 front image displaying portion    -   1306 second longitudinal section image displaying portion    -   1307 surgical guide image displaying portion    -   14 front-end lens    -   1500 SLO optical system    -   1501 dichroic mirror    -   1502 optical fiber    -   1503 collimating lens    -   1504 illuminating field diaphragm    -   1505 half mirror    -   1506 optical diaphragm    -   1507 condensing lens    -   1508 reflected light detector    -   1509 image generation part    -   16 SLO light source    -   O-300 optical axis of illuminating optical system    -   O-400 optical axis of observation optical system    -   O-400L optical axis of observation optical system for left eye    -   O-400R optical axis of observation optical system for right eye    -   O-400S optical axis of sub-observation optical system    -   O-500 optical axis of OCT optical system, optical axis of SLO        optical system    -   O-501 first optical axis    -   O-502 second optical axis    -   O-503 third optical axis    -   P-300 light path of illuminating optical system    -   P-400L light path of observation optical system for left eye    -   P-400R light path of observation optical system for right eye    -   P-500 light path of OCT optical system, light path of SLO        optical system    -   L0 light output from OCT light source unit    -   LC interfering light    -   LS measuring light    -   LR reference light    -   U0 front side focal position

What is claimed is:
 1. An ophthalmologic microscope comprising: anilluminating optical system for illuminating a subject's eye; anobservation optical system that comprises an observation optical systemfor left eye and an observation optical system for right eye to observethe subject's eye illuminated by the illuminating optical system; anobjective lens through which an optical axis of the observation opticalsystem for left eye and an optical axis of the observation opticalsystem for right eye of the observation optical system commonlypenetrate; and an OCT optical system for scanning a measuring light totest the subject's eye with Optical Coherence Tomography; wherein theobservation optical system, the objective lens, and the OCT opticalsystem are placed in such a way that the optical axis of the OCT opticalsystem does not penetrate through the objective lens through which theoptical axis of the observation optical system penetrates, and theoptical axis of the observation optical system and the optical axis ofthe OCT optical system are non-coaxial; and further comprising an SLOoptical system that scans a light ray which is a visible ray, a nearinfrared ray, or an infrared ray and guides the light to the subject'seye so as to become substantially coaxial with the optical axis of theOCT optical system, and the SLO optical system being configured suchthat the ophthalmologic microscope observe an area including a sectionof the subject's eye where the OCT optical system scans, with the SLOoptical system.
 2. The ophthalmologic microscope according to claim 1,wherein the OCT optical system comprises: a first optical member thatguides a light from an OCT light source to a first optical axisdirection; a first reflecting member that guides the light guided to thefirst optical axis direction to a second optical axis directionsubstantially perpendicular to the first optical axis direction; asecond optical member that relays the light guided to the second opticalaxis direction; a second reflecting member that guides the light relayedby the second optical member to a third optical axis directionsubstantially perpendicular to the second optical axis direction; and anobjective lens for OCT that is placed on the third optical axisdirection and irradiates a prescribed section of the subject's eye withthe light guided to the third optical axis direction.
 3. Theophthalmologic microscope according to claim 1, further comprising adeflection optical element that commonly scans a measuring light of theOCT optical system and a light ray of the SLO optical system.
 4. Theophthalmologic microscope according to claim 1, wherein the objectivelens has either a partial shape of a circular lens or a shape ofcircular lens with a cutout or hole, and the optical axis of the OCToptical system penetrates through a portion where the objective lensdoes not exist, or through a cutout or hole provided in the objectivelens.
 5. The ophthalmologic microscope according to claim 4, wherein theobjective lens is divided in two, with one part of the divided lensbeing as the objective lens and the other being as an objective lens forOCT through which the optical axis of the OCT optical system penetrates.6. The ophthalmologic microscope according to claim 1, furthercomprising an objective lens position control mechanism that adjusts aposition of the objective lens or the objective lens for OCT.
 7. Theophthalmologic microscope according to claim 1, wherein the OCT opticalsystem and the SLO optical system are detachably unitized.
 8. Theophthalmologic microscope according to claim 1, further comprising adetachable front-end lens on a light path between the subject's eye andthe objective lens to observe a retina of the subject's eye.